This report presents a case of carcinoma ex pleomorphic adenoma （Ca-ex-PA） of the buccal region. A 68-year-old man was referred to our hospital because of a mass in the left buccal region. Clinical examination showed an elastic hard, painless, movable mass measuring 50× 40 mm. The overlying skin and mucosal surface were intact and did not adhere to the mass. There was no facial nerve paralysis, and careful examination of the cervical region revealed no palpable lymph node. MR revealed a well-defined, 42 × 31 × 31 mm lesion in the left buccal area, of moderately high intensity on T1-weighted images and high intensity on T2-weighted images. We performed an incisional biopsy via an intraoral approach under local anesthesia, and histological examination of the specimen showed Ca-ex-PA, with the malignant component suspected to be salivary duct carcinoma （SDC）. The tumor was excised via a transbuccal approach under general anesthesia. Pathological findings of the surgical specimen were the same as those of the biopsy specimen, and the tumor was finally diagnosed as non-invasive Ca-ex-PA. As of 2 years 8 months postoperatively, the patient has had no facial nerve paralysis, salivary fistula, or evidence of recurrence or metastasis of disease.
